Heater construction



Aug. 13, 1940. R. E. WILSON 2,211,703

- firm-Er; cousfhuc'rion Original Filed Dec. 2a, 1933 s- Sheets-Sheet 1iNVENTOR {sobert E. Wz'won swim/M3 ATTORNEY Aug.13, 1940. R. E. wlLsoN 12,211,708

HEATER CONSTRUCTION Original Filed Dec. 28, 1933 5 Sheets-Shae; 2

. INVENTQR Robert Wilson ATTORNEY Aug. 13, 1940. R. E. WILSON HEATERCONSTRUCTION 3 Sheet-Sheet 5 Original Filed Dec. 28, 1933 M .hlLm N Q1'fiwxmD a, A @QQQ- Patented Aug. 13, 1940 UNITED STATES PATENT OFFICEHEATER OONSTB-UGHON Robert E. Wilson White Plains, N. Y., assignor toStandard Oil Company (Indiana), Chicago, 111., a, corporation of IndianaContinuation of application Serial No. 704,272, December 28, 1933. Thisapplication June 16, 1937, Serial No. 148,556

4Glaims.

ber of the furnace to the radiant heat of the burner flames is attained.

Another object is to provide a pipe still or heater of the characterdescribed, incorporating a plurality of radiant tube banks the tubes ofwhich are directly exposed on all sides to the radiant heat of theflame.

A further object is the provision of a still, of the characterdescribed, wherein all of the tube headers are readily accessible from apoint outside of the furnace walls for cleaning or replacement of thetubes.

Other objects, the advantages, and use of the invention will become moreapparent after reading the following specification and appended claims,and after consideration of the drawings forming a part of thespecification, in which:

Fig. 1 is a vertical sectional view of a pipe still constructed inaccordance with the invention,

Fig. 2 is a sectional view substantially along the line IIII of Fig. 1,

Fig. 3 is a view similar toFig. 2 of a pipe still illustrating anotherembodiment of the invention,

Fig. 4 is a fragmentary sectional view along the line IVIV of Fig. 3,and r Fig. 5 is a diagrammatic view illustrating a modification of thefluid flow circuit disclosed in preceding Figs. 1 to 4 inclusive.

In general the pipe still selected for illustration herein comprises aconventional brick housing I providing a combustion chamber 2 and aconvection section 3 separated from the combustion chamber by a verticalbridge wall 4, a plurality of vertical banks of radiant tubes 5 in thecombustion chamber, groups of burners 8, projecting through the sidewalls and/or floor of the combustion chamber, between each of thevertical banks of radiant tubes 5, roof tubes 1, and convection orabsorption tubes 8 located within the "convection section 3;

With reference particularly to Fig. 2 of the drawings, it will be notedthat the vertical banks of radiant tubes 5 virtually divide thecombustion chamber into a plurality of vertically extending sections. Inthe present instance I have chosen to arrange the tube banks so as todivide the combustion chamber into four such sections, each having itsown array of burners, although it will be apparent that the number oftube banks employed may be varied at will to suit the particularrequirements for which the pipe still or furnace is designed.

The burners 6 may be arranged in groups of two for each section of thecombustion chamber, one extending through each of the side walls 9 ofthe combustion chamber. This arrangement of the burners, one at each endof the several combustion sections, serves to provide substantialuniformity of radiant heat to the radiant tubes 5 forming the lateralconfines of the so-called sections, thus to aid in the efficienttransfer of heat to the fluid and vapor contents of the tubes.

In Fig. 1, I have illustrated an arrangement of the tubes 5 comprisingthe vertical banks in the radiant or combustion chamber of the furnacewhereby each tube may be subjected, without interference from adjacenttubes, to the radiant heat of burners 6 located at opposite sides of thetube. This arrangement is characterized by the staggering of the tubesof one vertical rank, or the bank, with respect to the remainingvertical rank, of the bank, so that a tubein one rank may not have ashielding effect upon any other tube in the adjacent rank. As a resultof this arrangement both sides of the tubes in each bank are equallysubjected to the direct radiant heat of the adjacent burners with theexception, obviously, of the first and last single tube rankslocatedadjacent to the forward wall H of the combustion chamber andbridge wall 4 respectively.

I have indicated, schematically, in Fig. 1, the flow diagram preferablyemployed. It will be noted that the input or fresh feed enters thefurnace tubes through the lowermost of the convection tubes 8, and afterpassing upwardly.-

through the convection tubes, is conducted through the roof tubes 1,which may be suspended, in the conventional manner, from the as may beseen by the' rearward bank it) of the tubes [5 located upon the bridgewall l.

Inasmuch as the hot gases from the burners 6 follow a course in thegeneral direction of the bridge wall i and thereafter flow over thebridge wall, the heat applied to those tubes making up the rearwardbanks in the combustion chamber of the furnace will receive added heatby convection. This characteristic of the furnace materially aids in theprincipal objective of the furnace, that of accelerated heat transfer tothe fluid contents of the tubes. The several banks of radiant tubes 5may be expected to provide some baiiie efiect so that a substantialportion of the hot gases is urged upwardly between the banks from theadjacent group of burners and thereafter caused to flow toward thebridge wall 6 and finally through the convection section into a flue l0leading to the furnace stack.

As a further aid to quick heating the tubes may be of relatively smalldiameter with respect to the size of tube customarily employed in theconventional type of tube still or heater. When such tubes are employedI prefer to arrange the tubes in multiple pass as in the mannerillustrated diagrammatically in Fig. 5. In the flow diagram of Fig. 5the radiant tubes 5a are arranged with adjacent vertically aligned pairsconnected in parallel, through suitable manifolds H which may be locatedin the header boxes iii of the still or furnace wall structure. The rooftubes la may be similarly arranged to increase rate of flow. If desired,the multiple pass arrangement of the tubes 5a may be carried out in thesame manner as are the convection tubes to in Fig. 5. In this event thearrangement would obviously apply only to the intermediate banks Idaeach comprising two vertical ranks, the adjacent pairs of tubes, one ineach rank being connected in parallel. The same arrangement isapplicable, if desired, to the roof tubes la.

The number of tubes in each multiple pass should be determined from therequired rate of flow and diameter of the individual tubes. When tubesof small diameter are used I prefer to employ heat resistant alloy tubespacer (not shown) to prevent sagging of the tubes.

In Figs. 3 and 4 I have illustrated another embodiment of the inventiondiffering from that heretofore described only as to the disposition ofthe burners 6. Instead of arranging the burners along opposite sidewalls 9 as shown in l and 2, one pair between each pair of adjacent tubebanks, I locate all of the burners along the floor or" the combustionchamber in a plurality of rows, one row between each pair of tube banks.Openings it through the floor of the combustion chamber are providedthrough which the burners 6 extend so as to direct their flames upwardlybetween the banks of radiant tubes. Passageways 2! may be formed in thefurnace foundation to permit an operator to adjust and service theburners.

While all of the species of the invention herein illustrated anddescribed have included a general flow diagram wherein the fluid to betreated passes in succession through the convection tubes 8 or 8a, theradiant roof tubes 1 or la, and the radiant tubes 5 or tea, it may befound that for some purposes an arrangement wherein the fluid flows fromthe convection tubes into the radiant tubes 5 or 5a and thereafterthrough the radiant roof tubes is more desirable.

I have provided in the pipe stills or furnaces herein describedrelatively simple construction aarmcs which is admirably fitted for usein the uick cracking of hydrocarbons as well as non-cracking"distillation processes requiring rapid heating without cracking. Inaddition, the advantageous structural characteristics of the ordinarytype of pipe still or preheater have been entirely preserved, such asready access to the tube headera is in both combustion and convectionsections as for cleaning or the removal of the tubes for repair orreplacement and the disposition of all of the burners 8 where they maybe reached easily for adjustment or repair.

While I have described my invention by the use of specific examples hisnot intended that such details shall be regarded as limitations upon thescope of the invention except insofar as included in the accompanyingclaims.

This application is a continuation of my application Serial No. 704,272,flied December 28, 1933.

I claim:

1. Apparatus for heating hydrocarbon oil to cracking temperaturecomprising a combustion chamber, a plurality of vertical banks ofinterconnected heat-absorbing tubes disposed in said combustion chamberand arranged in a plurality of spaced parallel banks to divide thecombustion chamber into a plurality of parallel heating sections, meansfor connecting tubes in each bank to cause hydrocarbon fluid to passthrough all of the tubes of one bank prior to entering the tubes ofanother parallel bank, means interconnecting the groups ofinterconnected heat-absorbing tubes in series for conducting oiltherethrough in succession, separate means for producing hot products ofcombustion disposed intermediate successive vertical banks, saidseparate means of the hot products of combustion from the com- I bustionchamber receive added heat by convection from the hot products ofcombustion.

2. Apparatus for heating hydrocarbon fluid to conversion temperaturecomprising combustion chamber defined by walls, a plurality of verticalbanks of interconnected heat-absorbing tubes disposed in said combustionchamber and arranged in a plurality of spaced parallel banks to dividethe combustion chamber into a plurality of sections, means forconnecting tubes in each bank to cause hydrocarbon fluid to pass throughall of the tubes of one bank prior to entering the tubes of anotherparallel bank, means for interconnecting adjacent groups ofinterconnected tubes in series for conducting hydrocarbon fluidtherethrough in succession from the vertical bank of interconnectedtubes closest one of said walls to the bank closest the opposite wall,separate means for producing hot products of combustion disposedintermediate successive vertical banks, said separate means and saidvertical banks being adapted to cause a relatively large portion of saidhot products of combustion to pass through substantially the entirespace between vertical banks to thereby heat the hydrocarbon fluidpassing through the tubes by heat radiated directly from the hotproducts of combustion and absorbed on both sides thereof, and means forremoving products of combustion from the'combustion chamber in the samegeneral direction as the hydrocarbon fluid flowing from the tubesclosest one wall to the tubes closest the opposite wall whereby tubes inthe vertical banks nearest the point of removal of the products ofcombustion and said opposite wall receive added heat by convectiontherefrom.

3. Apparatus for heating hydrocarbon fluid to conversion temperaturecomprising a furnace defined by walls and a roof, a bridge wallseparating the furnace into a combustion chamber and a convectionchamber, a bank of tubes in the convection chamber, a bank of tubesadjacent the roof of the furnace, a plurality of spaced vertical banksof interconnected heat-absorbing tubes in the combustion chamber todivide the combustion chamber into a plurality of sections, means forconnecting tubes in each bank to cause hydrocarbon fluid to pass throughalloi the tubes of one bank prior to entering the tubes of anotherparallel bank, means for interconnecting adjacent groups of the verticalbanks of tubes in series for conducting hydrocarbon fluid'therethroughin succession from the vertical bank of intercon- I nected tubes closestthe wall opposite the bridge wall to the bank closest the bridge wall,means for connecting the tubes of the convection section, the roof tubesand the vertical bank of tubes closest the wall opposite the bridge wallfor passage oi hydrocarbon fluid therethrough in the .order named,separate means for producing hot products of combustion disposedintermediate successive vertical banks, said separate means and saidvertical banks being adapted to cause a relatively large portion of saidhot products of combustion to pass through substantially the entirespace betwwn vertical banks to thereby heat the hydrocarbon fluidpassing through the tubes by heat radiated directly from the hotproducts of combustion and absorbed on both sides thereof, and means forremoving products of combustion from the combustion chamber in the samedirection as the hydrocarbomfluid' passing from the vertical banks oftubes closest the wall opposite the bridge wall to the vertical banks oftubes closest the bridge wall whereby the vertical banks nearest thepoint of removal of the products of combustion from the combustionchamber .for passage through the convection chamber and the bridge 'walireceive added heat by convection therefrom.

4. A method of heating hydrocarbon fluids to elevated temperature whichcomprises passing the hydrocarbon fluid in series flow through asuccession of serially connected and spaced vertical banks of tubesarranged in a combustion chamber to subdivide it into a plurality ofheat-= ing sections whereby the hydrocarbon fluid flows from the banksof tubes closest one of the boundary surfaces of the combustion chamberin series through said intermediate banks of tubes to the bank of tubesclosest the opposite boundary surfaoa'supplying hot products ofcombustion to.

each heating section, subjecting the tubes to heat radiated directlyfrom hot products of combustion supplied to each heating section tothereby apply radiant heat to both sides of each of the tubes of theintermediate banks, and withdrawing hot products of combustion from allof said heating sections adjacent one end of the combustion chamber sothat there is an increase in the application of convection heat tosucceeding vertical banks of tubes as the hydrocarbon fluid flowstherethrough in series and greater amounts of convection heat areapplied to the banks of the series closest said mentioned oppositeboundary surface,

